Password Protect PDF
Add AES-256 encryption to PDF documents to protect sensitive information, or remove existing passwords when you have the current credentials. Set separate user and owner passwords with granular permission controls for printing, copying, and editing. All encryption happens locally in your browser — passwords never leave your device.
What does this tool do?
The Password tool provides AES-256 encryption for PDF documents, the strongest encryption standard supported by the PDF specification. You can add password protection to unencrypted PDFs or remove passwords from encrypted files when you have the credentials. It supports dual-password architecture: a user password required to open the document, and an optional owner password for controlling permissions. Granular permission flags let you restrict printing, copying text, and other operations even after the document is opened.
How it works
Using MuPDF's encryption capabilities, the tool applies PDF standard security handlers. When protecting a document, it encrypts the PDF content streams with AES-256 in CBC mode using a key derived from your password. The user password controls document opening. The owner password (if set) controls permission modifications. Permission flags are embedded in the encryption dictionary and enforced by compliant PDF viewers. When removing protection, it decrypts the content and writes an unencrypted PDF version.
Features
- AES-256 encryption (the strongest standard the PDF spec supports)
- Separate user (open) and owner (permissions) passwords
- Toggle print and copy permissions independently
- Remove existing password protection when you have the credentials
- Encryption happens entirely in your browser — passwords never transmitted
- Compatible with all major PDF viewers and editors
How to use
- 1
Upload your PDF
Drag the PDF you want to encrypt or decrypt onto the drop zone. The tool detects if the file is currently encrypted.
- 2
Choose protection or removal
Select Protect to add encryption to an unencrypted PDF, or Remove to decrypt a password-protected file.
- 3
Set passwords for protection
Enter a user password (required to open the document). Optionally set an owner password for permission control. Strong passwords should be 8+ characters with mixed case, numbers, and symbols.
- 4
Configure permissions
Set permission flags: allow or disallow printing, and allow or disallow copying text and graphics. These apply when the document is opened with the user password.
- 5
Apply and download
Click Protect to encrypt or Remove to decrypt. The resulting PDF downloads with your security settings applied.
Common use cases
Secure confidential business documents
Add password protection to financial reports, contracts, and sensitive business communications before email transmission or cloud storage.
Protect personal information
Encrypt documents containing personal identification, medical records, tax returns, or other private information.
Create restricted distribution copies
Set owner passwords to prevent printing and copying while allowing viewing, creating read-only reference copies.
Remove passwords for workflow integration
Decrypt password-protected files received from external parties to enable automated processing in systems that can't handle encrypted PDFs.
Tips & best practices
- AES-256 passwords cannot be recovered — store them in a secure password manager or you will lose access to the document
- Use the owner password feature to create documents that can be viewed but not printed or copied
- For maximum security, use strong passwords: 12+ characters with uppercase, lowercase, numbers, and special characters
- The Remove function requires the current password — this tool cannot crack or bypass PDF encryption